1. Field of the invention
This invention relates to an improved apparatus for the formation of images used as a laser-beam printer, electrophotographic copier, etc.
2. Description of the prior art:
It has been known that apparatuses for the formation of images are provided with a first tray and a second tray. The recording paper on which an image has been formed is ejected into the first tray with its face upward (with the surface having the formed images facing upward). The recording paper is ejected into the second tray with its face down (with the surface having the the formed images facing downward). In such image formation apparatuses, for example, as shown in FIG. 5, the second tray 106 in which the recording paper is ejected with its face downward is positioned upwards the body of the apparatus. There is a route 107 for turning paper over provided between the paper-ejection rollers 139 and the second tray 106. The recording paper is ejected by the paper-ejection rollers 139 with its face up, passes through the route 107 for turning paper over, and is thus supplied to the second tray 106. The recording paper ejected by the paper-ejection rollers 139 can also be directly supplied to the first tray 105. In the downstream direction of paper-flow past the paper-ejection rollers 139, there are guides 104. Each of the guides 104 looks like the letter L when seen from the side, and it is supported at its curved section so that it can rotate. By rotation around the curved section of each of the guides 104, it is possible to switch selectively between supplying of the recording paper to the first tray 105 and to the route 107 for turning paper over. That is, when the recording paper is ejected directly into the first tray 105, each of the guides 104 is rotated to the left (shown as a dotted outline in FIG. 5) so that the recording paper does not touch the guides 104. In contrast, when the recording paper is guided into the route 107 for turning paper over, the said guides 104 are rotated to the right (shown as the solid outline in FIG. 5) so that the leading edge of each guide 104 is near the paper-ejection rollers 139. As a result, the recording paper is sent so as to enter the route 107 for turning paper over.
In general, in image-formation apparatuses, the recording paper is readily curled by the paperejection rollers 139 when being ejected by the paperejection rollers 139. To prevent the curling of the recording paper at the time of ejection by the paperejection rollers 139, it is necessary to dispose the paper-ejection rollers 139 at as high a position as possible to thereby have the paper ejected upwards whenever possible. However, since the guides 104 are disposed near the paper-ejection rollers 139, the recording paper ejected upwards from the paper-ejection rollers 139 touches the said guides 104, so that the direction in which the recording paper is sent may be suddenly changed downwards, resulting in the curling thereof. For this reason, the guides 104 must be in as high a position as possible. However, when the recording paper is guided into the route 107 for turning paper over, it is necessary to set the leading edge of each guide 104 below the region of the ejection by the paper-ejection rollers 139, so there are boundaries within which the guides 104 must be set. Therefore, if the center of rotation 104a of each guide 104 is set above, then when each of the guides 104 is rotated upward so that the recording paper will have to be ejected directly into the first tray 105, the guides 104 will touch the paper-ejection rollers 139. Thus, it is not possible to set the center of rotation 104a of each of the guides 104 above, and it is therefore difficult to prevent the curling of the recording paper when the recording paper is sent to the first tray 105. If the center of rotation 104a of each of the guides 104 is set in a lower position, when the recording paper is introduced into the route 107 for turning paper over, the direction in which the recording paper is sent cannot be smoothly changed, also resulting in the curling of the recording paper.